It is often desirable in the natural gas and oil industries to withdraw samples directly from a pipeline for analysis or measurement of various variables. Various instruments are used for this purpose, such as calorimeters, gravitometers, and hydrogen sulfide analyzers. The pipeline can be tapped and a sample drawn directly therefrom, however the pressure of the fluid in a pipeline is often too high for use in the analyzing or measuring instruments. Pipelines carry natural gas at pressures as great as 5000 psig, while many gas analyzing instruments cannot use samples at greater than 100 psig.
U.S. Pat. No. 4,346,611 to Welker ("the '611 patent") demonstrates the use of one type of regulator which is inserted into a pipeline to withdraw a sample and regulate the pressure thereof. The device is inserted into a pipeline so that the tip of the device is near the center of the pipeline, where the samples drawn are the most representative of the pipeline flow.
A regulator is located near the tip of device which reduces the pressure of the sample. In the case of a gas, though, the sudden drop in pressure of the fluid as it flows past the regulator, causes a sudden drop in temperature as well. This effect, known as the Joule-Thomson effect, can cause freezing or liquid carry over into the instrument. Such occurrences can cause damage to the insertion device or the instruments.
To counter the Joule-Thomson effect, regulator tips often have thermal fins attached thereto, thus increasing the surface area of the tip. This allows more thermal energy from the pipeline flow to be absorbed by the tip just beyond the point of regulation. The '611 patent discloses the use of such thermal fins, and most of the regulator tips used in the industry, such as those made by Welker Engineering Company of Sugar Land, Tex., use thermal fins for the same purpose.
Nonetheless, further means are required to counter the Joule-Thomson effect in insertion instrument regulators. It is thus an object of the present invention to provide a regulator tip which will counter the cooling effects of pressure regulation.
It is a further object of the present invention to provide an insertion instrument regulator with a heated tip. Other objects of the invention will become apparent from the specification described herein below.